Guide for catheterism

ABSTRACT

A guide is used for the selective catheterism of anatomic structures and for placing therapeutic instruments.

OBJECT OF THE INVENTION

The present invention relates to the use of a guide for the selective catheterism of anatomic structures and for placing therapeutic instruments.

TECHNICAL PROBLEM

The passing of a flexible guide called “a guide wire” into the different natural conduits of the human body such as those present in the digestive, hepato-pancreatic, urinary, genital, respiratory, cardiovascular systems is generally necessary for introducing therapeutic instruments (“medical devices”) up to the site to be treated. The guide should therefore go through the different conduits with an increasingly reduced width up to the site to be treated. In all these conduits, obstacles may be present preventing proper navigation of the guide and not allowing easy access to said site to be treated. The obstacles may be of different natures, either natural or not, and be formed, for example by the sinuous anatomy of the conduit, or be due to the presence of tumors, calculi, foreign bodies, or further to the presence of folds in the mucosa. In order to navigate in these sinuous and/or obstructed conduits, or to circumvent these obstacles, present guides are provided with a flexible end. Indeed, when the guide is confronted with one of these obstacles, it may be diverted and come to impact or touch the walls of the natural conduit which may cause an injury (edema) and/or with a deterioration of the guide making the continuation of the navigation more difficult. Further, the dimensions of the guide, in particular those of its distal end, opposite to the therapist, should allow navigation of the guide in very narrow conduits, the diameter of which decreases gradually as the guide progresses in the natural routes to be explored.

Solutions have been proposed in the different documents of the state of the art such as the “Loop Tip Wire Guide” described in document WO 2006/039217.

However, the solutions currently present do not allow total resolution of these technical difficulties and therefore do not satisfy the therapists.

MAIN CHARACTERISTIC ELEMENTS OF THE INVENTION

With the present invention, it is possible to navigate in a network of conduits, the diameter of which decreases gradually as the guide progresses in the routes to be explored.

Complementarily, with the present invention, it is possible to avoid injuries or contusions due to the sharp end of the guide, to mucosas and endothelial walls, and the navigation of the guide may be facilitated by means of the particular shape of its end.

According to the invention, a guide for catheterism is proposed, the body of which is provided at its distal end with an appendage or an endpiece having a three-dimensional shape, preferably axisymmetrical around the axis of revolution of said guide. This three-dimensional shape may for example be ovoidal, spheroidal, ellipsoidal. Preferably this shape does not have any edge or acute angle and in particular has a profile perpendicular to the longitudinal axis which has a quasi-constant radius of curvature. By quasi-constant is meant a variation comprised between 50 to 200% and preferably between 75 and 125%.

More particularly, the guide is characterized in that the appendage or endpiece has in the plane perpendicular to the longitudinal axis of said guide body at least one dimension greater than the diameter of said guide body. Preferably, at least one dimension and preferably one dimension in the plane perpendicular to the longitudinal axis and in particular the maximum diameter of the appendage is significantly greater than the diameter of the body of the guide.

By significantly is meant an increase by at least 20%, preferably 30%, preferably 50%, preferably 100%.

According to another alternative, the appendage has significantly greater dimensions than the body of the guide both in the radial and axial directions.

According to a particularly preferred embodiment, the appendage or the endpiece of the guide is detachable from the body of said guide. The dissociation may advantageously occur actually within the human or animal body, i.e. in situ, and preferably on the site to be treated. For this purpose, the presence of dissociation means are provided, which will allow the appendage or the endpiece to be detached or dissociated from the body of said guide on command from the therapist.

Advantageously, dissociation means are provided in order to make the appendage detachable from the guide actually within the human or animal body. This appendage may of course also be detachable outside the human body. As an example, the release of the appendage of the guide may be accomplished by the action of dissociation means already present on the guide.

Dissociation of the appendage or of the endpiece results from voluntary action of the therapist and should not by any means take place suddenly.

Preferably, dissociation is carried out by a mechanical action on command from the therapist.

Means for controlling the dissociation means may also be provided and advantageously allow detachment of the appendage or the endpiece as soon as the site to be treated is reached.

Preferably, the integrality of the appendage or endpiece is detached from the guide so as to avoid the presence of abrasive or blunt portions which may act on the surrounding tissues and injure them.

The attachment of the detachable appendage or endpiece on the guide is carried out preferentially by physico-chemical interactions.

By the terms of “physico-chemical interactions” are meant all the interactions which allow adhesion of two identical or different materials, such as electrostatic, steric, hydration interactions, capillary condensation, interaction due to covalent forces, interaction due to Van der Waals forces, overlapping interactions, etc. (“Intermolecular & Surfaces” 2^(nd) edition, JACOB ISRAELACHVILI, Academic Press (1992). ISBN: 0-12-375181-0 and “Fundamentals of adhesion”, LIENG-HUANG Lee. Plenum Press New York (1991). ISBN: 0-306-43470-9).

Preferably, all mechanical interactions are therefore excluded.

Alternatively, the attachment of the appendage or endpiece on the body of the guide is carried out with a substance having adhesive properties.

Advantageously, the connection between the appendage or the endpiece and the body of the guide is selected depending on the physico-chemical properties of the materials used for their respective manufacturing.

According to another particularly preferred embodiment, the material of the appendage or of the endpiece of the guide is advantageously deformable or extensible by deployment.

The material of the appendage or of the endpiece of the guide is advantageously elastic.

According to another embodiment, it is possible to also contemplate that the appendage be not present on the guide before it is introduced into the human body, it only appears in the human body for example by the action of an inflatable membrane.

Alternatively, the material of the appendage or of the endpiece of the guide may not be deformable, this is in particular the case if the endpiece is detachable.

More particularly, this appendage may be made in a metal, organic (for example polymeric, elastomeric), silica, ceramic or composite material. The appendage should be preferably be biocompatible (such as for example as described in the standard EN ISO 10993-1) and unaffected by the surrounding medium.

Preferably, the material in which this appendage or this endpiece is made has a heat expansion coefficient greater than that of the material in which the guide is made.

This appendage may be solid, hollow or crossed by one or more orifices.

Its outer surface will preferably be treated in order to obtain a lower friction coefficient than the anatomic environment and therefore have improved roughness so as to allow and facilitate navigation.

The appendage may be made in the same materials as those used for making the guide.

Preferentially, the body of the guide is made with at least one of the following materials: cellulose acetate, cellulose nitrated, silicon, polyethylene, high density polyethylene, polyethylene terephthalate, polyurethane, polytetrafluoro-ethylene, polyamide, polyester, polyorthoester, polyvinyl chloride, polypropylene, acrylonitrile-butadiene-styrene, polycarbonate, polyurethane, nylon silicones, polyanhydride and other equivalents.

Preferentially, the appendage or the endpiece is made with at least one of the following materials: cellulose acetate, cellulose nitrate, silicone, polyethylene, high density polyethylene, polyethylene terephthalate, polyurethane, polytetrafluoro-ethylene, polyamide, polyester, polyorthoester, polyvinyl chloride, polypropylene, acrylonitrile-butadiene-styrene, polycarbonate, polyurethane, nylon silicones, polyanhydride or other equivalents.

The present invention advantageously allows single use of the guide for catheter.

DESCRIPTION OF SEVERAL PREFERRED EMBODIMENTS OF THE INVENTION

According to a first embodiment, the guide for catheterism is provided at its distal end with an appendage or endpiece having a three-dimensional shape, preferably axisymmetrical, around the axis of revolution of said guide.

Preferably, the guide is characterized in that the appendage or endpiece has in the plane perpendicular to the longitudinal axis of said guide a dimension greater than the diameter of said guide.

Preferably, the appendage of endpiece of the guide is firmly attached to the body of said guide.

Alternatively, the appendage or the endpiece of the guide is detachable from the body of said guide.

Preferably, the material of the appendage or of the endpiece of the guide is deformable.

Alternatively, the material of the appendage or of the endpiece of the guide is not deformable.

FIGS. 1-4 each illustrate a preferential shape of the appendage present at the distal end of the guide. These appendages have a three-dimensional shape and preferably are axisymmetrical around the axis of revolution of the body of the guide. At least one dimension is preferably a dimension in a plane perpendicular to the longitudinal axis and in particular a diameter and preferably the maximum diameter (φ₂) of the appendage 10 is significantly greater than the diameter (φ₁) of the body 1 of the guide.

By significantly, is meant an increase by at least 20% preferably by at least 50% and preferably by at least 100% of the maximum diameter (φ₂) of the appendage 10 relatively to the (constant (φ₁) diameter of the body 1 of the guide.

In a first embodiment illustrated in FIG. 1, the appendage significantly juts out from the body 1 of the guide both in the axial direction (L₂) and in the radial direction (φ₂).

In other embodiments, more particularly illustrated in FIGS. 2 and 3, l the dimension (maximal diameter φ₂) of the appendage only significantly exceeds the diameter (φ₁) of the body of the guide 1 in the radial direction. The dimension in the axial direction essentially corresponds to the distal tip of the body of the guide.

In another embodiment, more particularly illustrated in

FIG. 4, the guide is curved, the axis of revolution of the appendage preferably being the axis 100 of the guide when the latter is straightened out (i.e. in the non-curved position).

In another embodiment as the one illustrated in FIG. 5, the appendage is deformable or extensible allowing a change in shape and/or in volume, allowing a transition from a non-deployed state to a deployed state or vice versa, the deployed state being defined by the fact that at least one dimension and in particular one dimension perpendicular to the longitudinal axis, and preferably the diameter (φ₂) of the appendage, is significantly greater than the diameter (φ₁) of the body of the guide while the non-deployed state corresponds to a state where the appendage does not have any dimension in the plane perpendicular to the longitudinal axis, greater than the maximum dimension and in particular than the diameter of the body of the guide.

In this particularly preferred embodiment of the invention, the appendage 10 is preferentially formed by an extensible or inflatable element 11 such as a membrane or a balloon, which may be inflated by a gas or a fluid 12.

In this case, the volume of the appendage 10 is for example obtained by simply injecting a pressurized fluid through an internal channel 2 present in the guide 1.

According to an embodiment illustrated in FIG. 6, the appendage 10 is extensible or deformable. By extensible, is meant a change in volume of the appendage while by deformable is meant a change in its shape.

Advantageously, the appendage may pass from a deployed state to a non-deployed state by modification of its shape and/or of its volume. The deployed state is defined by the fact that at least one dimension and in particular one dimension perpendicular to the longitudinal axis of the body of the guide and preferably the maximum diameter of the appendage is significantly greater than the diameter of the volume of the guide while the non-deployed state corresponds to a state where the appendage does not have any dimension greater than the diameter of the body of the guide.

According to another preferred embodiment, the appendage may be made in a shape memory material such as shape memory polymers which will modify their state or their shape by a rise in the temperature of the ambient medium. This rise in temperature may quite simply occur by application of an external means such as an electric current or simply by the influence of the body temperature.

FIG. 7 illustrate the means for detaching or dissociating the appendage 10 or the endpiece (detachable) from the body of the guide 1. The different steps (FIGS. 7 a-7 c) required for detaching the appendage or the endpiece from said means are illustrated therein.

The dissociation means illustrated in FIG. 7 are for example formed by a catheter 4 which exerts pressure on the outer face of the appendage 10 or of the endpiece.

Preferably, the end of the catheter exerting this pressure comprises a ring or circlet ensuring uniform distribution of the pressure on the appendage or the endpiece. Preferably, the presence of this ring increases the stiffness of the end of the catheter.

FIG. 8 illustrate means for detaching or dissociating the appendage 10 or the endpiece (detachable) from the guide body 1. The different steps (FIGS. 8 a-8 c) required for detaching the appendage or the endpiece with said means are illustrated therein.

The firm attachment means illustrated in FIG. 8 are formed by an internal conduit or channel 6 present inside the guide body 1 and one of the open ends of which coincides with the distal end, relatively to the therapist, of the guide.

This conduit or channel 6 allows a pressurized fluid to be conveyed from the proximal end, relatively to the therapist, of the guide.

This fluid will exert sufficient pressure on the internal face of the appendage 10 or endpiece so as to cause its integral dissociation from the guide 1.

Preferably, this fluid is a liquid. Alternatively, this fluid is a gas. Preferably, this liquid is water. Alternatively, this liquid is a saline buffer.

A device comprising both types of aforementioned means for detaching the detachable appendage or endpiece from the guide is another preferred embodiment.

EXAMPLES 1. Selective Catheterism of the Biliary Route.

Selective catheterism of the biliary route through the papilla of Vater is technically difficult and may be accomplished either directly with a catheter or with a guide. Oddi's sphincter is covered with a mucosa and, when catheterism is not successful during the first maneuvers, repeated handling of catheters or of a guide which impacts in the mucosa, creates an edema, making the procedure more difficult.

The type of guide described above, provided with an atraumatic and rounded end, not having any angulation, allows reduction of the trauma of the mucosa and of the edema resulting from this. Also, it helps the flexible end of the guide to adapt to the S-shape of the papilla, in order to find its way towards the biliary route.

Guides modified according to the present invention have been tested in animal models. These tests have revealed that this particular embodiment of the present invention allows significant reduction in the tendency to impaction of the distal end of the guide in a complex structure.

In order to be able to continue to use the guide, in narrower conduits, the appendage is voluntarily detached from the guide, inside the animals by action of the catheter on the guide.

The appendage used for this catheterism is a shape similar to the one illustrated in FIG. 2. This appendage is detached from the body of the guide by action of the dissociation means. The tested material forming the appendage is polyester. The dimensions of appendage for this test are:

-   φ₁: diameter of the guide, at its flexible end. -   φ₁=0.035″ (0.889 mm) in this example. -   φ₂=maximum diameter of the appendage. -   φ₂=1.7 mm in this example. -   L₂: height of the appendage. -   L₂=2.5 mm in this example.

2. Selective Catheterism of the Pancreas.

Selective catheterism of the pancreas is technically difficult and may be accomplished either directly with a catheter, or with a guide. Oddi's sphincter is covered with a mucosa and when the catheterism is not successful during the first maneuvers, repeated handling of catheters or a guide which impacts in the mucosa, creates an edema, making the procedure more difficult. The type of guide described above, provided with an atraumatic and rounded end, not having any angulation, allows reduction of the trauma at the mucosa and of the edema resulting from this. Also, it helps the flexible end of the guide to adapt to the S-shape of the papilla, in order to find its way towards the pancreas.

Guides modified according to the present invention have been tested in animal models. These tests have revealed that this particular embodiment of the present invention allows significant reduction in the tendency to impaction of the distal end of the guide in complex structures.

The appendage used for this catheterism is a spherical shape. The tested material forming the appendage is polyester. The dimensions of the appendage for this test are:

-   φ₁: diameter of the guide, at its flexible end. -   φ₁=0.035″ (0.889 mm) in this example. -   φ₂=maximum diameter of the appendage. -   φ₂=1.5 mm in this example. -   L₂: height of the appendage. -   L₂=1 mm in this example.

Dimensions of the Appendage in the Case of Catheterism of the Biliary Route and of the Pancreas:

-   1.2φ₁<φ₂<3 mm -   0.5 mm<L₂<5 mm -   φ₂: diameter of the guide at its flexible end. -   φ₂: maximum diameter of the appendage. -   L₂: height of the appendage. 

1-10. (canceled)
 11. A guide for catheterism, the body of which is provided at its distal end with an appendage or endpiece having an axisymmetrical three-dimensional shape, around the axis of revolution of the body of said guide, comprising: means for dissociating said appendage or said endpiece relatively to the body of said guide; and means for controlling said dissociation means.
 12. The guide according to claim 11, wherein the dissociation means associated with the control means allow action in such a way that said appendage or said endpiece is made detachable from the body of said guide in situ or inside the human body.
 13. The guide according to claim 11, wherein the dissociation means act by mechanical action.
 14. The guide according to claim 11, wherein said appendage or said endpiece is attached to the body of said guide via physico-chemical interactions.
 15. The guide according to claim 11, wherein said appendage or said endpiece is attached to the body of said guide with a substance having adhesive properties.
 16. The guide according to claim 11, wherein the appendage or said endpiece is deformable or extensible.
 17. The guide according to claim 15, wherein said appendage or said endpiece allows transition between a non-deployed state and a deployed state by modification of its shape and/or of its volume.
 18. The guide according to claim 1, wherein the appendage or endpiece has at least one dimension in a plane perpendicular to the longitudinal axis, the maximum diameter of the appendage being greater than the maximum diameter of the body of the guide.
 19. The guide according to claim 11, wherein the dissociation means are formed by a catheter exerting pressure on the appendage or endpiece.
 20. The guide according to claim 11, wherein the dissociation means are formed by an internal conduit or channel and one of the open ends of which coincides with the distal end of the guide, the conduit or channel allowing a pressurized fluid to be conveyed.
 21. The guide according to claim 11, wherein the axisymmetrical three-dimension shape is ovoidal, spheroidal or ellipsoidal. 